将下列句子改为被动语态 He bought a bike t

将下列句子改为被动语态 He bought a bike t
将下列句子改为被动语态
1.He bought a bike two days ago .A bike（）（）two days ago
2.We must send more satellites into space
More satellites （）（）（）into space
3.Scientists may clone humans some day
Humans（）（）（）（）scientists some day
4.He can’t finish his work in such a short time.
His work（）（）（）in such a short time